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Q1. | The power is measured in terms of decibles in case of |

A. | Electronic equipment [Correct Answer] |

B. | Transformers [Wrong Answer] |

C. | Current transformers [Wrong Answer] |

D. | Auto-transformers [Wrong Answer] |

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Explanation:-
Answer : ADiscuss it below :!! OOPS Login [Click here] is required to post your answer/resultHelp other students, write article, leave your comments |

**Also Read Similar Questions Below :**

⇒ In A.C. circuit laminated iron is invariably used in order to

Reduce eddy current loss

Increase heat radiation

Make assembly cheap and easier

Reduce circuit permeability

⇒ A parallel resonant circuit can be used

As a high impedance

To reject a small band of frequencies

Both (A) and (B)

To amplify certain frequencies

⇒ Selectivities of different resonance circuits are compared in terms of their

Impedances

Reactances

Frequencies

Band widths

⇒ Which of the following waves has the highest value of peak factor '?

Square wave

Sine wave

Half wave rectifier sine wave

Triangular wave

⇒ The form factor of D.C. supply voltage is always

Zero

0.5

Unity

Infinite

⇒ The r.m.s. value of a half-wave rectified current is 100 A. Its value for full-wave rectification would be____ amperes.

141.4

200

200/π

40/π

⇒ Capacitive reactance is more when

Capacitances is less and frequency of supply is less

Capacitance is less and frequency of supply is more

Capacitance is more and frequency of supply is less

Capacitance is more and frequency of supply is more

⇒ The transient currents are associated with the

Changes in the stored energy in the inductors and capacitors

Impedance of the current

Applied voltage to the circuit

Resistance of the circuit

⇒ The power taken by a 3-Φ load is given by the expression

√3 V

_{L}I

_{L}sinΦ

√3 V

_{L}I

_{L}cosΦ

3 V

_{L}I

_{L}sinΦ

3 V

_{L}I

_{L}cosΦ

⇒ Ohm is the unit of all of the following except

Inductive reactance

Capacitive reactance

Resistance

Capacitance

⇒ In a parallel R-C circuit, the current always ____the applied voltage.

Lags

Leads

Remains in phase with

None of the above

⇒ Power factor of the following circuit will be unity

Inductance

Capacitance

Resistance

Both (A) and (B)

⇒ Which of the following statement is incorrect ?

Resistance is a passive element

Voltage source is an active element

Conductance is a passive element

Current source is a passive element

⇒ The voltage of domestic supply is 220 V. This figure represents-

Mean value

r.m.s. value

Peak value

Average value

⇒ The time constant of a series R-C circuit is given by

R/C

RC

^{2}

RC

R

^{2}C

⇒ The negative maximum of a cosine wave occurs at

30

45

90

180

⇒ The period of a wave is

The same as frequency

Time required to complete one cycle

Expressed in amperes

None of the above

⇒ The r.m.s. value of pure cosine function is

0.5 of peak value

0.707 of peak value

Same as peak value

Zero

⇒ Which of the following circuit component opposes the change in the circuit voltage

Inductance

Capacitance

Conductance

Resistance

⇒ While drawing vector diagram for a series circuit the reference vector is

Voltage

Current

Power

Phase angle

⇒ In an A.C. circuit, a low value of kVAR compared with kW indicates

Low efficiency

High power factor

Unity power factor

Maximum Load current

⇒ What inductance will give the same reactance as a capacitor of 2 µF when both are at 50 Hz?

5 H

10 H

15 H

20 H

⇒ For the full wave rectified sine wave the r.m.s. value is

0.707 I

_{max}

0.636 I

_{max}

0.318 I

_{max}

Zero

⇒ The power factor of a series R-L-C circuit at its half-power points is

Unity

Lagging

Leading

Lagging or leading

⇒ The r.m.s. value and mean value is the same in the case of

Triangular wave

Sine wave

Square wave

Half wave rectified sine wave

⇒ When an alternating current passes through an ohmic resistance the electrical power converted into heat is

Apparent power

True power

Reactive power

None of the above

⇒ Capacitors for power factor correction are rated in

kW

kVA

kV

kVAR

⇒ The time period of a sine wave is 1/50 seconds. Its frequency is

20 Hz

30 Hz

40 Hz

50 Hz

⇒ The frequency of domestic power supply in India is

200 Hz

100 Hz

60 Hz

50 Hz

⇒ The safest value of current the human body can carry for more than 3 second is

4 mA

9 mA

15 mA

25 mA